Problem: The equation of hyperbola $H$ is $\dfrac {(y+4)^{2}}{9}-\dfrac {(x+9)^{2}}{16} = 1$. What are the asymptotes?
Answer: We want to rewrite the equation in terms of $y$ , so start off by moving the $y$ terms to one side: $\dfrac {(y+4)^{2}}{9} = 1 + \dfrac {(x+9)^{2}}{16}$ Multiply both sides of the equation by $9$ $(y+4)^{2} = { 9 + \dfrac{ (x+9)^{2} \cdot 9 }{16}}$ Take the square root of both sides. $\sqrt{(y+4)^{2}} = \pm \sqrt { 9 + \dfrac{ (x+9)^{2} \cdot 9 }{16}}$ $ y + 4 = \pm \sqrt { 9 + \dfrac{ (x+9)^{2} \cdot 9 }{16}}$ As $x$ approaches positive or negative infinity, the constant term in the square root matters less and less, so we can just ignore it. $y + 4 \approx \pm \sqrt {\dfrac{ (x+9)^{2} \cdot 9 }{16}}$ $y + 4 \approx \pm \left(\dfrac{3 \cdot (x + 9)}{4}\right)$ Subtract $4$ from both sides and rewrite as an equality in terms of $y$ to get the equation of the asymptotes: $y = \pm \dfrac{3}{4}(x + 9) -4$